Synthesis Of Novel Phenyl Phosphine And Phosphine Oxide And Research Of Flame Retarded Polymer

Polycarbonate and epoxy resin, very important polymer materials, have outstanding properties, such as good mechanical properties and chemical stability etc. Therefore, they are widely used in the fields of construction, automobiles, electronic and electric devices, etc. But the polymers are easily flammable and subjected to various mandatory controls. A widely known method to impart flame retardancy is to add a halogen-containing compound to the resin. Although halogenated compounds show good flame retardancy and have been used widely for several decades, their use has been curtailed in many countries because of toxic and corrosive fumes released during combustion. Environmental concerns about halogenated flame retardants are the driving forces behind the development of cost effective, halogen-free alternatives. Organo-phosphorus flame retardant, as an alternative, possess the properties of "enveriment-friendly" and high efficient. It could impart good flame retardancy to the resin and has the advantages of low smoke and low toxicity. In recent years, the organic-phosphorus flame retardants have become a hot topic of the flame retardants developed neighborhood.In this work, novel flame retardants additives, phenylene phenyl phosphine oligomer (PPPO) and bis (2-tienyl) phenylphosphine (BTPP) were designed and synthesized. On the base, novel curing agent, m-aminophenylene phenyl phosphine oxide oligomer (APPPOO) and bis (3-amino-2-tienyl) phenylphosphine oxider (ABTPPO) were synthesized. Four organic-phosphorus compounds were characterized using Fourier transform infrared spectroscopy (FTIR),1H,13C,31P nuclear magnetic resonance (NMR) spectroscopy and mass spectrometer (MS), and the effect of reaction parameters on the yield were studied.PPPO and BTPP were used to impart flame retardancy to PC by melt blending. Combustion behaviours of PC/PPPO and PC/BTPP systems were assayed by limiting oxygen index (LOI), vertical burning test (UL-94) and cone calorimeter test (CONE). The results indicated that PC/6wt.%PPPO and PC/3wt.%BTPP passed UL-94V-0rating with3.0mm samples and the LOI values of PC/6wt.%PPPO and PC/3wt.%BTPP were34.1and36.5%, respectively; PC/8wt.%PPPO and PC/6wt.%BTPP also passed UL-94V-0rating with1.6mm samples and the LOI values were36.3and38.5%, respectively. The CONE test results revealed that the parameters, peak heat release rate (PHRR), total heat released (THR), average specific extinction area (ASEA) and average mass loss rate (AMLR), etc, decreased compared to these of PC. Thermogravimetric analysis results showed that in N2and air, the initial degradation temperature of PC/PPPO and PC/BTPP systems decreased but the residual char yields increased. The analysis of scanning electron microscopy (SEM) and FTIR reflected that PPPO and BTPP occurred thermo-oxidative degradation and formed phosphoric and polyphosphoric acids at lower temperature. The acids promoted the char-forming, and then a protective layer formed to stop the propagation of heat and oxygen to melt polymer matrix during combustion. Therefore, it prevents the polymer from further burning. The result of mechanical properties test indicated that the negative effects of PPPO and BTPP on the tensile and Izod impact strength of PC were slight. Especially, the flexural strength of PC increased due to the addition of PPPO and BTPP. After water resistance test, the mass loss of the systems was only0.2%. The effect of the test on thermal stability and mechanical properties was low, and the samples kept good flame redartancy after the test.The epoxy resin (EPO) was cured using1,3-phenylene diamine (PDA), APPPOO and ABTPPO as curing agents, and LOI and UL-94test were carried out for the epoxy resin systems. The LOI values of EPO/APPPOO and EPO/ABTPPO were34.8and38.3%, respectively. The sample with3.0mm thickness can pass UL-94V-1rating and the sample with1.6mm thickness pass UL-94V-2rating. The CONE test results indicated that PHRR and THR, etc, obviously decreased compared to these of EPO/PDA system. TGA results revealed that the flame retarded epoxy resin degraded at low temperature but the yield of the residue char increased. The results of SEM and FTIR showed that the flame retarded epoxy resin occured thermo-oxidative degradation and formed phosphoric and polyphosphoric acids. The acids promoted the char-forming, and then a protective layer formed to stop the propagation of heat and oxygen to the polymer matrix during combustion. Therefore, it prevents the polymer from further burning. The result of mechanical properties test indicated that the negative effects of APPPOO and ABTPPO on the tensile, flexural and Izod impact strength of epoxy resin were slight. The results of water resistance test indicated that the water uptake of flame retarded resin was low and the samples kept good flame redartancy after the test.